For a considerable period of time, there has been a market for easily assembled and disassembled objects which may be formed from flat sheets of chip board, corrugated board and the like. Inexpensive household furniture, such as storage cabinets, particularly for clothing, have been formed by flat panels secured together by fasteners. Children's playhouses and the like have been formed from interlocking sheets without fasteners.
These types of products have a number of advantages. Since they are made from flat panels, which are generally boxed and sold in cartons, there is a substantial saving in space, the unassembled components naturally occupying substantially less space than the assembled product. The products are generally lightweight, easily assembled and disassembled, and are inexpensive.
A major disadvantage, however, is that objects made from two dimensional, flat panels generally lack structural rigidity. They can readily be bent, the panels frequently come apart, unless permanently secured together, and they generally will not support much weight.
Examples of this type of construction will be found in the U.S. Pat. Nos. 1,258,086; 1,533,011; 2,075,259; 2,832,100; and 4,523,418, spanning a period of almost 70 years.
It is an object of this invention to provide three dimensional, rather than two dimensional, structural beams for objects such as playhouses and articles of household furniture which are made from flat panels.
Another object of this invention is to provide blanks for fabricating three dimensional structural beams which blanks may be manufactured from flat stock, pre-cut and scored while still flat, and shipped and sold, while still flat and unassembled.
Yet another object of the invention is to provide blanks for assembly into three dimensional structural members which require no independent securing means.